A press-forming device includes a punch and a die, as a mold to be measured, and a strain measurement means arranged within the mold and measuring a strain amount generated by press-forming. The strain measurement means is positioned at the press-direction side relative to a radius end of a die shoulder on the material flow-out side when the mold is positioned at a lower dead point of press-forming. The strain measurement means is preferably positioned within a region defined by a surface which is away from the center of curvature of a curved surface of the mold by the distance ten times R, where R is a curvature radius of the curved surface.